If you look to the night sky Sept. 27, you'll get to see a Super Harvest Moon total lunar eclipse, which also happens to be the final eclipse in a lunar tetrad. If that sounded like a whole lot of overwhelming gibberish, let's break it down one item at a time. What is a super-moon? As the moon orbits around the Earth, its distance from our planet varies by roughly 30,000 miles. When a full moon occurs at the perigree, or closest point to Earth, we call it a super-moon.